1. Field of the Invention
The field of this invention relates to cannulas through which surgical instruments are inserted and more particularly to fixation devices to hold the cannula in one or more positions with respect to the incision in the patient.
2. Description of the Prior Art
Endoscopic surgical procedures involve insertion of instruments through incisions or punctures as well as the placement of the scope and associated light source through other incisions or punctures. During such procedures, a variety of instruments are used through one or more cannulas for access to different locations. As a result, the cannula through which the instruments are inserted and manipulated must be shifted to gain better access to the specific location. Additionally, in arthroscopic procedures (a subset of the category of endoscopic procedures), to allow better viewing of the surgical site, the site is kept under a slight liquid flow pressure to facilitate access and to keep body fluids from occluding the scope. For this reason it is advantageous to maintain a seal between the cannula and the body even if the cannula position requires shifting. Allowing the seal to be broken can result in fluids escaping and hitting the surgeon. Apart from a need to have the option of repositioning the cannula after fixation, another objective of the cannula should be simple and reliable insertion or removal. These benefits are found in the present invention of the cannula fixation system.
Fixation devices have been used in the past on catheters. The purpose of these devices has been to hold the catheter in position, after setting, for the duration of the procedure. An example of a urinary catheter with a corrugated expanding sleeve is shown in U.S. Pat. No. 3,970,090 (Loiacono). This device is intended to be retained in a tubular passageway and, like all catheters is not open at the end to accept surgical instruments. Other examples of passageway catheters with multifold sleeves are U.S. Pat. Nos. 5,827,304 (Hart) and 6,254,571 (Hart). These two patents show the use of the sleeve to remove occlusive material from a body passage. There are patents showing cannulas with dual fold or dual element sleeves, such as U.S. Pat. Nos. 5,122,122 (Allgood) and 5,836,913 (Orth et al.) although these devices are difficult to use and not adjustable.
The following U.S. patents show slots forming strips that expand on compression to anchor but not to seal cannulas or catheters: U.S. Pat. No. 1,621,159 (Evans); U.S. Pat. No. 3,108,595 (Overment); U.S. Pat. No. 3,261,357 (Roberts et al.); U.S. Pat. No. 3,896,804 (Ekbladh et al.); U.S. Pat. No. 3,938,530 (Santomieri); U.S. Pat. No. 4,043,338 (Homm et al.); U.S. Pat. No. 4,608,965 (Anspach et al.); U.S. Pat. No. 4,699,611 (Bowden) and U.S. Pat. No. 5,053,009 (Herzberg). Some patents use spirally cut strips instead of longitudinally oriented strips such as GB 955,490 (Brooke) and U.S. Pat. No. 5,275,975 (Foshee). Yet other US designs involve inflatable fixation devices, such as: U.S. Pat. No. 3,915,171 (Shermeta); U.S. Pat. No. 3,952,742 (Taylor); U.S. Pat. No. 4,077,412 (Moossun); U.S. Pat. No. 4,861,334 (Nawaz); U.S. Pat. No. 5,002,557 (Hasson) and U.S. Pat. No. 5,147,316 (Castillenti). Other US designs employ collet fingers to anchor, such as: U.S. Pat. No. 3,039,468 (Price); U.S. Pat. No. 3,717,151 (Collett) and U.S. Pat. No. 5,445,615 (Yoon). Finally of general interest in the areas of fixation devices for catheters or cannulas are U.S. Pat. No. 4,655,752 (Honkanen et al.)(cannula body with fixed annular ribs); U.S. Pat. No. 5,009,643 (Reich et al.) (threaded cannula body) and U.S. Pat. No. 5,234,455 (Mulhollan) (cannula with distal annular radially extending lip).
None of the foregoing prior art devices have all the benefits afforded by the present invention which presents a cannula that is easily inserted or removed and whose position can be easily altered while it remains sealingly in contact with the incision in the patient. (The term xe2x80x9cincisionxe2x80x9d will be understood to mean any portal through which the cannula is inserted, regardless of how the portal was created.) These and other advantages and aspects of the present invention will be more readily appreciated by those skilled in the art from a review of the description of the preferred embodiment and the claims which appear below.
Accordingly, it is an object of this invention to produce a cannula fixation system enabling a user to, with one hand, place a cannula into a portal, secure it within the portal and subsequently adjust the cannula position and re-secure it.
It is also an object of this invention to produce a cannula fixation system which sealingly secures a cannula in a portal while enabling adjustments of the cannula position within the portal without destroying the seal.
These and other objects of this invention are achieved by the preferred embodiment disclosed herein which is a cannula which features a fixation system that allows for easy insertion and removal. A flexible sleeve with corrugations and a proximal flange is slidably attached to the cannula. The distal end of the sleeve is fixedly attached near the distal end of the cannula, while the proximal end of the sleeve remains unattached. The flange serves as a splashguard and a finger retention device. The flange is pulled distally to stretch the sleeve and thereby reduce the outer diameter of the corrugations for insertion or movement of the sleeve. Upon release of the flange, the corrugations expand thereby creating a seal against the tissue surrounding the portal in the patient. The cannula body can be shifted longitudinally relative to the sleeve without destroying the sealing contact between the sleeve and the portal.